The invention relates to tires for heavy goods vehicles and in particular to tires that are provided with devices for deflecting lateral expulsions of water when a vehicle equipped with said tires runs along a roadway covered with water.
When driving in rainy weather, the maneuvers of passing or overtaking a heavy goods vehicle are often very fraught for other road users owing to the large amount of water that may be expelled laterally by said vehicle, which water, on reaching the windscreens of the other vehicles, considerably reduces visibility.
A heavy goods vehicle tire is in general made up of two beads intended to be in contact with a wheel rim, a crown provided with a tread having a running surface intended to be in contact with the ground when the vehicle is running, and two sidewalls for joining this tread to the beads.
Such a tire is reinforced by a carcass reinforcement extending from one bead to the other and a crown reinforcement located radially to the outside of the carcass reinforcement, this crown reinforcement comprising at least two superposed reinforcing plies, that is to say plies placed one against the other. Each ply of the crown reinforcement is in general made up of a plurality of reinforcements placed so as to make an angle ranging from 0° to 70° with the circumferential direction. However, it is not excluded for the angle of the reinforcements to be greater than 70°.
The tread of a heavy goods vehicle tire is provided with a sculpture formed from raised elements bounded by cuts (grooves and/or incisions) designed to ensure, among other things, that the tire adheres properly to a wet road.
The tire has a maximum width dimension L measured at its sidewalls when it is fitted onto its wheel and subjected to its nominal pressure and load conditions in use (L represents the maximum distance between the points on the sidewalls that are axially furthest apart).
European Patent EP 1 048 489 (corresponding to de Labareyre U.S. Pat. No. 6,460,584) describes the use of a device comprising at least one protuberance made of rubber compound provided on at least one of the sidewalls of the tire.
The purpose of the protuberance is to deflect/modify the path of the flow of liquid expelled so that this flow is not expelled excessively upwards, forming a spray that hampers the other road users, especially those overtaking or passing the vehicle.
The solution described in that patent makes it possible to limit the temperature rise inside the tread and especially near the ends of the crown reinforcement plies.
However, it appears that, when in use, the protuberance described in that patent loses its effectiveness as the tread wears away, since the protuberance, owing to the very wear, tends to become closer and closer to the surface of the roadway.